BeginPackage["Wikicode`Zinc`"]
Production::usage="Production[date] gives the annual world zinc production from the specified date."
Begin["`Private`"]
Production[from_Integer]:=Select[zincData["Production"],DateDifference[{from},#[[1]]] >= 0&]
zincData["Production"] =
MapAt[{Round@#} &, #, 1] & /@
Import["http://minerals.usgs.gov/ds/2005/140/ds140-zinc.xlsx"][[1,
6 ;; 117, {1, 10}]]
End[]
EndPackage[]
